Rangemaster, a germanium transistor based treble booster developed around 1965 in London, UK by a company called John E.

Dallas & Sons Limited. The Rangemaster was used to drive Tube

Amplifiers into saturation because (high) gain Tube Amplifiers were not available during the 60‘ties. Famous guitar players who created their unique sound with a treblebooster are: Rory Gallagher, Eric Clapton, Ritchie Blackmore, David Gilmour, Bryan May and Tony Iommi.